This invention relates to phonocardiographic analysis and, more particularly, to analysis of weak cardiac sounds.
It has long been recognized that heart sound identification is an important tool in diagnosing cardiac disease. A variety of methods have been, and are presently, used to detect and analyze heart sounds. The stethoscope allows a physician to listen directly to heart sounds. These sounds may also be amplified by electronic means. However, the weaker heart sounds, which primarily result from abnormal hemodynamic function, diastolic murmurs, coronary stenotic murmurs and the like, are often masked by respiration sounds. Accordingly, various methods have been proposed or used to separate or distinguish these weaker heart sounds from breathing sounds.
One such technique involves computer averaging of electrocardiographic signals without regard to synchronization of breathing. Although it is useful to eliminate undesirable noise waveforms to accentuate specific heart sound components, the resolution of weak sounds is sacrificed. Another resolution technique utilized involves having a patient hold his breath while the researcher or practitioner analyzes, by conventional means, a number of heart beats, such as five beats for example. This procedure is repeated until approximately two hundred heart beats have been analyzed. This method is uncomfortable for the patient and is inconvenient and burdensome for the technician.
The object of the present invention is to provide a method for quickly, easily and accurately distinguishing sounds generated by cardiac functions from breathing sounds. It is a further object of this invention to provide a method to quickly and accurately detect and display for subsequent diagnosis a broad range of heart sounds, particularly weak heart sounds. Another object of the present invention is to provide a means to distinguish sounds generated by cardiac function from breathing sounds. It is a further object of this invention to provide a means to quickly and easily detect, isolate and display a broad range of heart sounds, particularly weak heart sounds. And, although a need exists in the medical diagnostic art for such methods and means, none insofar as is known has been proposed or developed.